Before I discuss this, let me clarify a few things. I'm really anal. I start with the historical Combined Fleet OOB and modify it from there. I allocate my fleet by ship (warships only, not merchant ships) by region. I have a spreadsheet of the Combined Fleet going so far as to color code the DD classes (makes identifying who needs upgrades easier). I'll show an example later.
Initially, the IJN fleet is scattered to the four winds. After the SRA is liberated, here's how I plan on disbursing my fleet to defend my deserved empire.
KB
based in Tokyo
6x CV
4x BB (the old BCs)
2x CA
1x CL
18x DD
1 Fleet (Battle Fleet)
based in the SRA
1x CVL (Zuiho and later, Shoho)
1x CVE (Hosho, later transferred to 3 Fleet when Shoho arrives)
6x BB (+Yamato & Musashi when they arrive)
8x CA
2x CL (Kitakami & Oi)
1x CL
20x DD
8x SS (I class including 2x Glen carrying)
2 Fleet (Saigon (later Singapore) based to defend the SRA)
3x CA
1x CL
16x DD
8x SS (6x I class & 2x Ro class) Will get 2x Glen carrying when built
3 Fleet (Truk Based, to support SE Fleet)
1x CVL (Ryujo + Hosho when Shoho arrives)
5x CA
3x CL
15x DD
19x SS (10x I class including 2 Glen carrying for South Central Pac and 9x Ro class later based out of Rabaul)
4 Fleet (Kwajalein based to support the Pacific)
Later, surface ships will withdraw to 3 Fleet AO and 3 Fleet will take over defense of this area)
3x CL (including Tatsuta & Tenryu)
8x DD
12x SS (I class including 7x Glen carrying)
5 Fleet (Northern Force)
2x CL
4x DD
6x SS (I class, will eventually get 3x Glen carrying when built)
Replenishment Force
7x AO (the 18 & 19 kt)
1x CL
8x DD
SS Minelayers
4x SS (I-121 class minelayers - distributed around the globe to lay mines seemingly at random to cause the maximum havoc. [:D])
